I've been given an HTML document, it's full of <font> tags with size=4 and everything like that

I have to turn it into XHTML with inline styles.

No problem, he says (I say) until I realise that I have no idea what size=4 really means.

Anyone got any idea how to get a px or em value from this size?

Another "old" memory bank going?

These might be of help:

<font size="+1"></font>
<font size="+2"></font>
<font size="-1"></font>
<font size="-1"></font>

<font size="3" face="arial">

<div style="margin-left: 5em" class="nav-links">

Lastly, this handy table is something you might want to bookmark -- Reed Table

nice table, thanks!

You're welcome -- we all gotta help each other from time-to-time, as none of us can remember everything, especially migrating from system to system.